The Impact on the Ozone Layer of a Potential Fleet of Civil Hypersonic Aircraft.

The aeronautical community is currently researching technology that might lead to commercial hypersonic aircraft that would cruise at Mach 5–8 in the middle or upper stratosphere and would transfer passengers from London to New York or from Los Angeles to Tokyo in just a couple of hours. Depending on the engine technology to be adopted, these aircraft will potentially release substantial amounts of water vapor and nitrogen oxides around 30–40 km altitude. We show here that the operation of a large fleet of such aircraft could potentially deplete considerable amounts of ozone in the stratosphere, which would lead to a substantial increase in biologically damaging ultraviolet radiation reaching the Earth's surface. The calculations are based on a specific emission scenario, which carries large uncertainties but can easily be scaled to account for the type of aircraft engine to be eventually adopted, improved technology to be expected, and the size and operation conditions of the future aircraft fleet. Plain Language Summary: Commercial hypersonic aircraft, if developed in the future, will be flying at Mach 5 to 8 in the middle to upper stratosphere (30 to 40 km altitude) to carry passengers in a couple of hours from London to New York or from Los Angeles to Tokyo. Depending on the adopted technology and fleet size, the powerful engines of such airplanes may release substantial amounts of water and nitrogen oxides in the stratosphere, which could potentially damage the protecting ozone layer and hence increase the level of biologically damaging ultraviolet radiation reaching the Earth surface. The paper uses an advanced global atmospheric model to assess the impact of a potential fleet of hypersonic aircraft. Key Points: Hypersonic transport (HST) releasing nitrogen oxides and water vapor have the potential to reduce the stratospheric ozone abundancePer Tg injection of nitrogen oxides, the calculated ozone depletion is larger for aircraft flying at 30 km than 40 km altitudeOzone decrease near the HST flight altitude is reduced by about a third when temperature and dynamical feedbacks are taken into account [ABSTRACT FROM AUTHOR]